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Cunlong Li
732fd9f0b9
zram_read_page() picks the sync or async backing device read path based on whether the parent bio is NULL. zram_bvec_write_partial() passes its parent bio down, so for ZRAM_WB slots the read is dispatched asynchronously and zram_read_page() returns 0 while the bio is still in flight. The caller then runs memcpy_from_bvec(), zram_write_page() and __free_page() on the buffer, leaving the async read to write into a freed page. zram_bvec_read_partial() was switched to NULL in commit4e3c87b942("zram: fix synchronous reads") for the same reason; the write_partial counterpart was missed. Link: https://lore.kernel.org/[email protected] Fixes:8e654f8fbf("zram: read page from backing device") Reviewed-by: Christoph Hellwig <[email protected]> Reviewed-by: Sergey Senozhatsky <[email protected]> Signed-off-by: Cunlong Li <[email protected]> Cc: Jens Axboe <[email protected]> Cc: Minchan Kim <[email protected]> Cc: Yisheng Xie <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]>